Sheet post-processing apparatus

ABSTRACT

[Problem]A sheet bundle can be stacked with no displacement, a stacking property of the sheet bundle is improved, and sheet receiving time is shortened, which allows improvement of productivity. 
     [Solving Means]A sheet post-processing apparatus  1  includes sheet conveying means  10  for conveying a sheet  100  discharged by an image forming apparatus to a stacking tray  3 , jogger and stack means  30  including a pair of left and right joggers  31  that stacks the sheet  100  discharged by the sheet conveying means  10  while supporting and jogging the sheet  100 , and a support  20  that is able to be progressed and retreated, and supports a rear end portion of the sheet  100  discharged by the sheet conveying means  10  at a progressing position. In the sheet post-processing apparatus  1 , the jogger and stack means  30  is arranged above the stacking tray  3 , the support  20  is arranged between the stacking tray  3  and the jogger and stack means  30 , the sheet  100  discharged by the sheet conveying means  10  is supported by the pair of left and right joggers  31 , the rear end portion of the sheet  100  is placed on and jogged by the support  20  located at the progressing position to form a sheet bundle  110 , the pair of left and right joggers  31  is opened to drop the jogged sheet bundle  110  on the stacking tray  3 , the support  20  is retreated, and the rear end portion of the sheet bundle  110  placed on the support  20  is dropped and stacked on the stacking tray  3.

TECHNICAL FIELD

The present invention relates to a sheet post-processing apparatusconnected to an image forming apparatus such as a copying machine and aprinter.

BACKGROUND ART

Conventionally, there is well-known a sheet post-processing apparatusthat performs a jogger and stack process and a stapling process to asheet discharged from an image forming apparatus such as a copyingmachine and a printer. For example, in some sheet post-processingapparatuses, the sheets discharged from the image forming apparatus arestapled by stapling means, and a sheet bundle stapled by the staplingmeans is dropped and stacked on a stacking tray by opening jogger andstack means, and the subsequent sheets are discharged on the stackedsheet bundle by sheet conveying means while overlapped with the sheetbundle, and the next sheet bundle is formed by the jogger and stackmeans (e.g., refer to Patent Literature 1).

CITATION LIST Patent Literature

Patent Literature 1: JP 8-225227A

SUMMARY OF INVENTION Technical Problem

Sometimes the sheet discharged from the image forming apparatus such asthe copying machine and the printer is curled around a conveyingdirection due to a structure of a conveying system of the image formingapparatus, and there is a risk of displacing the sheet bundle due to thecurled sheet during the jogger and stack process.

The sheet bundle is dropped and stacked on the stacking tray, and thenext sheet is discharged and stacked on the stacked sheet bundle. Indropping the sheet bundle on the stacking tray, there is no means ofescape of air between the sheet bundles, and sometimes the stacked sheetbundle is displaced by the air.

The invention is made in view of above-described problem, and an objectof the invention is to provide a sheet post-processing apparatus thatcan stack the sheet bundle with no displacement to improve a stackingproperty of the sheet bundle and shorten sheet receiving time to improveproductivity.

Solution to Problem

In order to solve the above problems to achieve the object, the presentinvention is configured as follows.

According to a first aspect of the invention, a sheet post-processingapparatus includes: sheet conveying means for conveying a sheetdischarged by an image forming apparatus to a stacking tray; jogger andstack means including a pair of left and right joggers that stacks thesheet discharged by the sheet conveying means while supporting andjogging the sheet; and a support that is able to be progressed andretreated, and supports a rear end portion of the sheet discharged bythe sheet conveying means at a progressing position. At this point, thejogger and stack means is arranged above the stacking tray, the supportis arranged between the stacking tray and the jogger and stack means,the sheet discharged by the sheet conveying means is supported by thepair of left and right joggers, the rear end portion of the sheet isplaced on and jogged by the support located at the progressing positionto form a sheet bundle, the pair of left and right joggers is opened todrop the jogged sheet bundle on the stacking tray, and the support isretreated to drop and stack the rear end portion of the sheet bundleplaced on the support on the stacking tray.

According to a second aspect of the invention, in the sheetpost-processing apparatus according to the first aspect of theinvention, the support supports an inside in a width direction of therear end portion of the sheet.

According to a third aspect of the invention, in the sheetpost-processing apparatus according to the first aspect of theinvention, the pair of left and right joggers supports and jogs aleading end side portion and a leading end bottom portion of the sheetdischarged by the sheet conveying means, and the pair of left and rightjoggers is opened to drop a leading end side of the jogged sheet bundleon the stacking tray.

According to a fourth aspect of the invention, in the sheetpost-processing apparatus according to the first aspect of theinvention, the pair of left and right joggers is horizontally movablewith respect to a sheet discharge center position, operation to move thesheet bundle in one of the horizontal directions while the sheet bundleis jogged at the sheet discharge center position, open the pair of leftand right joggers at a stacking position, and retreat the support todrop and stack the sheet bundle on the stacking tray, and operation tomove the sheet bundle in the other of the horizontal directions whilethe sheet bundle is jogged at the sheet discharge center position, openthe pair of left and right joggers at the stacking position, and retreatthe support to drop and stack the sheet bundle on the stacking tray arerepeated, and the sheet bundle is stacked on the stacking tray whilealternately displaced.

According to a fifth aspect of the invention, in the sheetpost-processing apparatus, the pair of left and right joggers ishorizontally movable with respect to a sheet discharge center position,operation to move the sheet bundle in one of the horizontal directionswhile the sheet bundle is jogged at the sheet discharge center position,open the pair of left and right joggers at the stacking position, andretreat the support to drop and stack the sheet bundle on the stackingtray is repeated, and the sheet bundle is stacked on the stacking traywhile not alternately displaced.

According to a sixth aspect of the invention, the sheet post-processingapparatus according to the first aspect of the invention furthercomprising stapling means for stapling the sheet bundle jogged by thepair of left and right joggers. At this point, the pair of left andright joggers is opened to drop the leading end side of the sheet bundlestapled by the stapling means on the stacking tray, only the rear endportion of the sheet bundle is placed on the support, and the support isretreated to drop and stack the rear end portion the sheet bundle placedon the support on the stacking tray.

According to a seventh aspect of the invention, in the sheetpost-processing apparatus according to the sixth aspect of theinvention, the pair of left and right joggers is horizontally movablewith respect to a sheet discharge center position, operation to move thesheet bundle only in one of the horizontal directions while the sheetbundle is jogged at the sheet discharge center position, and staple thesheet bundle at a stapling position using the stapling means, operationto move and open the pair of left and right joggers at one of stackingpositions, and retreat the support to drop and stack the sheet bundle onthe stacking tray, operation to move the sheet bundle in one of thehorizontal directions while the sheet bundle is jogged at a sheetdischarge center position, and staple the sheet bundle at a staplingposition using the stapling means, and operation to move and open thepair of left and right joggers at the other of stacking positions, andretreat the support to drop and stack the sheet bundle on the stackingtray are repeated, and the sheet bundle is stacked on the stacking traywhile alternately displaced.

According to an eighth aspect of the invention, in the sheetpost-processing apparatus according to the sixth aspect of theinvention, the pair of left and right joggers is horizontally movablewith respect to a sheet discharge center position, the pair of left andright joggers repeats operation to move the sheet bundle in one of thehorizontal directions while the sheet bundle is jogged at the sheetdischarge center position, and staple the sheet bundle at a staplingposition using the stapling means, and operation to move and open thepair of left and right joggers at one of stacking positions, and retreatthe support to drop and stack the sheet bundle on the stacking tray, andthe sheet bundle is stacked on the stacking tray while not alternatelydisplaced.

According to a ninth aspect of the invention, in the sheetpost-processing apparatus according to any one of the sixth to eighthaspects of the invention, a sheet bundle holder is arranged at aposition where the sheet bundle jogged by the pair of left and rightjoggers is stapled, and the sheet bundle holder acts as a holding memberfor the sheet bundle to be stapled, and as a cover covering the staplingmeans.

According to a tenth aspect of the invention, in the sheetpost-processing apparatus according to any one of the first to ninthaspects of the invention, the sheet post-processing apparatus isarranged above the image forming apparatus, and the sheet conveyingmeans conveys the sheet sent from an upper portion of the image formingapparatus to the stacking tray.

Advantageous Effects of Invention

Thanks to the above configuration, the invention has the followingadvantageous effects.

In the first aspect of the invention, the jogger and stack means isarranged above the stacking tray, the support is arranged between thestacking tray and the jogger and the stack means, the sheet dischargedby the sheet conveying means is supported by the pair of left and rightjoggers, and the rear end portion of the sheet is placed on and joggedby the support located at the progressing position, so that the sheetbundle can smoothly be formed without displacing the sheet.Additionally, the pair of left and right joggers is opened to drop thejogged sheet bundle on the stacking tray, and the support is retreated,and the rear end portion of the sheet bundle placed on the support isdropped and stacked on the stacking tray. Therefore, the sheet bundlecan smoothly and quickly be dropped on the stacking tray, and thestacked sheet bundle is not displaced by the air because the air escapesto the rear end side of the sheet bundle.

In the second aspect of the invention, the support supports the insidein the width direction of the rear end portion of the jogged sheetbundle. Therefore, the displacement of the sheet can be reduced even ifthe sheet is curled around the conveying direction due to the structureof the conveying system of the image forming apparatus.

In the third aspect of the invention, the pair of left and right joggerssupports and jogs the leading end side portion and the leading endbottom portion of the sheet discharged by the sheet conveying means, andthe pair of left and right joggers is opened to drop the leading endside of the jogged sheet bundle on the stacking tray. Therefore, thestacked sheet bundle is not displaced by the air because the air escapesto the rear end side from the leading end side of the sheet bundle.

In the fourth aspect of the invention, the sheet bundle is stacked onthe stacking tray while alternately displaced, but the stacked sheetbundle is not displaced by the air when the sheet bundle is dropped andstacked on the stacking tray.

In the fifth aspect of the invention, the sheet bundle is stacked on thestacking tray while not alternately displaced, but the stacked sheetbundle is not displaced by the air when the sheet bundle is dropped andstacked on the stacking tray.

In the sixth aspect of the invention, the pair of left and right joggersis opened to drop the leading end side of the sheet bundle stapled bythe stapling means on the stacking tray, only the rear end portion ofthe sheet bundle is placed on the support, and the support is retreatedto drop and stack the rear end portion of the sheet bundle placed on thesupport on the stacking tray. Therefore, a staple used to staple thesheet bundle can be prevented from being caught on the pair of left andright joggers, but the sheet bundle is not displaced by the catch of thestaple.

In the seventh aspect of the invention, the stapled sheet bundle isstacked on the stacking tray while alternately displaced, the stapleused to staple the sheet bundle can be prevented from being caught onthe pair of left and right joggers, but the sheet bundle is notdisplaced by the catch of the staple.

In the eighth aspect of the invention, the sheet bundle is stacked onthe stacking tray while not alternately displaced, the staple used tostaple the sheet bundle can be prevented from being caught on the pairof left and right joggers, but the sheet bundle is not displaced by thecatch of the staple.

In the ninth aspect of the invention, the sheet bundle holder isarranged at the position where the sheet bundle jogged by the pair ofleft and right joggers is stapled, the sheet bundle holder holds thesheet bundle to be stapled, and the sheet bundle can be stapled withoutdisplacing the sheet bundle. Additionally, the sheet bundle holdercovers stapling means, so that a user can be prevented from inserting afinger in the position where the sheet bundle is stapled.

In the tenth aspect of the invention, the sheet post-processingapparatus is arranged above the image forming apparatus, and the sheetsent from the upper portion of the image forming apparatus can beconveyed to the stacking tray.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view of a sheet post-processing apparatus.

FIG. 2 is a front view of the sheet post-processing apparatus.

FIG. 3 is a side view of the sheet post-processing apparatus.

FIG. 4 is a perspective view of the sheet post-processing apparatus.

FIG. 5 is a configuration diagram of the sheet post-processingapparatus.

FIG. 6 is a sectional view of the sheet post-processing apparatus.

FIGS. 7( a) and 7(b) are views illustrating actuation of a support.

FIG. 8 is a view illustrating a stack and a jogger.

FIGS. 9( a) and 9(b) are views illustrating stacking of a sheet bundle.

FIGS. 10( a) to 10(c) are views illustrating a jogger and stack state.

FIGS. 11( a) to 11(c) are views illustrating a stapling state.

FIG. 12 is a view illustrating actuation of the case that stapling isnot performed.

FIG. 13 is a view illustrating actuation of the case that stapling isnot performed.

FIG. 14 is a view illustrating actuation of the case that stapling isperformed.

FIG. 15 is a view illustrating actuation of the case that stapling isperformed.

DESCRIPTION OF EMBODIMENT

Hereinafter, a sheet post-processing apparatus according to anembodiment of the invention will be described. The embodimentillustrates the best mode of the invention, but the invention is notlimited to the embodiment.

(Configuration of Sheet Post-Processing Apparatus)

FIG. 1 is a plan view of a sheet post-processing apparatus, FIG. 2 is afront view of the sheet post-processing apparatus, FIG. 3 is a side viewof the sheet post-processing apparatus, FIG. 4 is a perspective view ofthe sheet post-processing apparatus, and FIG. 5 is a configurationdiagram of the sheet post-processing apparatus.

In a sheet post-processing apparatus 1 of the embodiment, an apparatusbody 2 includes a stacking tray 3, a support 20, jogger and stack means30, stapling means 40, and sheet conveying means 10. In a bottom portionof the apparatus body 2, registration members 90 are provided at rightand left ends while protruded downward. The sheet post-processingapparatus 1 is arranged while the registration members 90 are insertedin the upper portion of the image forming apparatus such as a copyingmachine and a printer, and a sheet discharged from the image formingapparatus is sent in the sheet post-processing apparatus 1 from below.The sheet conveying means 10 is configured so as to convey the sheetsent from the upper portion of the image forming apparatus to thestacking tray 3. The jogger and stack means 30 and the stapling means 40perform a jogger and stack process and a stapling process, and theprocessed sheet bundle is stacked on the stacking tray 3.

FIGS. 6 to 9 illustrate actuation of the sheet post-processingapparatus. FIG. 6 is a control diagram of the sheet post-processingapparatus, FIG. 7 illustrates actuation of a support, FIG. 7( a)illustrates a state in which the support is retreated, FIG. 7( b)illustrates a state in which the support is progressed, FIG. 8 is aperspective view illustrating a stack and a jogger, FIG. 9 illustratesstacking of a sheet bundle, FIG. 9( a) is a view illustrating a state inwhich a leading end side of the jogged sheet bundle is dropped on astacking tray, and FIG. 9( b) is a view illustrating a state in which arear end side of the jogged sheet bundle is dropped on the stackingtray.

The sheet conveying means 10, the support 20, the jogger and stack means30, and the stapling means 40 are arranged in the apparatus body 2 ofthe embodiment. The sheet conveying means 10 includes a conveying guide11 and a conveying roller 12, and conveys a sheet 100 discharged fromthe image forming apparatus onto the stacking tray 3 from a positionbelow the apparatus body 2. For example, the conveying roller 12 isdriven by conveyance driving means 200 including power transmissionmeans such as a motor, a belt, and a gear. The conveyance driving means200 drives the conveying roller 12 to convey the sheet 100.

The three supports 20 are horizontally arrayed at positions above thestacking tray 3, for example. The support 20 can be progressed andretreated in a sheet discharge direction with respect to the apparatusbody 2, a rear end portion of the sheet 100 discharged from the sheetconveying means 10 is supported at a progressing position of the support20, and the sheet is dropped at a retreating position. For example, thesupport 20 is driven by a support driving means 201 including powertransmission means such as a motor and a cam. The support 20 isprogressed and retreated by the support driving means 201.

The jogger and stack means 30 includes a pair of left and right joggers31 that perform stack and jogger. In the apparatus body 2, the pair ofleft and right joggers 31 can horizontally be moved with respect to asheet discharge center position. The pair of left and right joggers 31having a U-shape in section includes a lower guide 31 a, an upper guide31 b, and a coupling guide 31 c. The pair of left and right joggers 31stacks and jogs the sheet discharged from the sheet conveying means 10while supporting both side end portions and both side bottom portions ata leading end of the sheet.

The pair of left and right joggers 31 is provided in a moving body 38with a slide lever 32. In jogging, and opening and closing the pair ofleft and right joggers 31, the pair of left and right joggers 31 isdriven by jogger moving means 202 including power transmission meanssuch as a motor and an actuation shaft. In horizontally moving the pairof left and right joggers 31, the pair of left and right joggers 31 isdriven by jogger movement driving means 203 including power transmissionmeans such as a motor, a gear, and a belt. The sheets 100 are jogged bythe pair of left and right joggers 31.

The jogger and stack means 30 is arranged above the stacking tray 3, andthe supports 20 are arranged between the stacking tray 3 and the joggerand stack means 30. Therefore, a leading end side of the sheet 100discharged by the sheet conveying means 10 is supported by the pair ofleft and right joggers 31 of the jogger and stack means 30, and the rearend portion is stacked and jogged on the supports 20 located at theprogressing positions, thereby forming a sheet bundle 110. At thispoint, the supports 20 support an inside in a width direction of therear end portion of the sheet 100, and support the inside in the widthdirection of the rear end portion of the sheet bundle 110 jogged by thesupports 20, so that displacement of the sheet bundle 110 can be reducedeven if the sheet 100 is curled around a conveying direction due to astructure of a conveying system of the image forming apparatus.

The leading end side of the jogged sheet bundle 110 is dropped on thestacking tray 3 by opening the pair of left and right joggers 31, andonly the rear end portion of the sheet bundle 110 is placed on thesupport 20. Then, the supports 20 are retreated to drop the rear endportion of the sheet bundle 110 placed on the supports 20 on thestacking tray 3.

In stacking the sheet 100, the pair of left and right joggers 31 havingthe U-shape in section includes the lower guide 31 a, the upper guide 31b, and the coupling guide 31 c, and supports both the side end portionsand both the side bottom portions at the leading end of the sheet 100.Therefore, the leading end portion of the jogged sheet bundle 110 isdropped on the stacking tray 3 by opening the pair of left and rightjoggers 31. The rear end portion of the sheet bundle 110 is placed onthe supports 20, the support 20 is arranged between the stacking tray 3and the jogger and stack means 30, the support 20 is located below thepair of left and right joggers 31, and the rear end portion of the sheetbundle 110 stacked on the support 20 is dropped and stacked on thestacking tray 3 by retreating the support 20. Therefore, the sheetbundle 110 can smoothly and quickly be dropped on the stacking tray 3.Additionally, the stacked sheet bundle 110 is not displaced by airbecause the air escapes from the leading end side to the rear end sideof the sheet bundle 110 when the sheet bundle 110 is dropped.

The pair of left and right joggers 31 is arranged above the stackingtray 3, the support 20 is arranged between the stacking tray 3 and thepair of left and right joggers 31, and the support 20 is located belowthe pair of left and right joggers 31. Therefore, the support 20 isretreated to drop and stack the sheet bundle 100 on the stacking tray 3in a short time, the next sheet 100 can be received by the pair of leftand right joggers 31, and the receiving time can be shortened to improvethe productivity.

The stapling means 40 is arranged on the right side of the apparatusbody 2 while incorporated in the apparatus body 2, and the sheet bundle110 jogged by the jogger and stack means 30 is stapled. In the stapling,a corner portion at a rear end of the jogged sheet bundle 110 is closedwith a staple by a well-known method.

FIGS. 10( a) to 10(c) are views illustrating the jogger and stack state,and FIGS. 11( a) to 11(c) are views illustrating the stapling state. Onthe right side of the apparatus body 2, a sheet bundle holder 50 isarranged at a position where the sheet bundle 110 jogged by the joggerand stack means 30 is stapled. The sheet bundle holder 50 acts as aholding member for the sheet bundle 110 to be stapled, or as a covercovering the stapling means 40.

Referring to FIG. 10, the pair of left and right joggers 31 of thejogger and stack means 30 is located at the jogger and stack position,the sheet bundle holder 50 acts as the cover covering the stapling means40, and a user is prevented from inserting a finger in the staplingposition. In the state of FIG. 10, a protrusion 33 formed in a slidelever 32 supporting the right jogger 31 is located at the position wherean arm 34 is not actuated. In the arm 34, when an end portion 36 a of alink 36 is depressed through an auxiliary lever 35, an end portion 36 bdepresses a contact 37 a of a safety switch 37 to turn off the safetyswitch 37.

When the pair of left and right joggers 31 of the jogger and stack means30 is located at the jogger and stack position, because the protrusion33 formed in the slide lever 32 supporting the right jogger 31 islocated at the position where the arm 34 is not actuated, the arm 34does not depress the end portion 36 a of the link 36 through theauxiliary lever 35, and the link 36 is not actuated. Therefore, thesafety switch 37 is in an off state in which current is not passed, andthe actuation of the stapling means 40 is prohibited.

Referring to FIG. 11, the pair of left and right joggers 31 of thejogger and stack means 30 is moved to the stapling position to performthe stapling. At the stapling position, the protrusion 33 formed in theslide lever 32 supporting the right jogger 31 actuates the arm 34, thearm 34 depresses the end portion 36 a of the link 36 through theauxiliary lever 35, the link 36 is actuated, the end portion 36 bdepresses the contact 37 a of the safety switch 37 to put the safetyswitch 37 into an on state in which the current is passed, and thestapling means 40 is actuated to perform the stapling.

(Actuation of Sheet Post-Processing Apparatus)

A control device 300 receives a command of the number of sheets 100 tobe jogged from a control device of the image forming apparatus, drivesthe conveyance driving means 200, the support drive 201, the joggerdriving means 202, and the jogger movement driving means 203, andperforms shift stacking actuation and one-way stacking actuation in thecase that the stapling is not performed and the shift stacking actuationand the one-way stacking actuation in the case that the stapling isperformed.

[Shift Stacking Actuation in the Case that Stapling is not Performed]

The actuation in the case that the stapling is not performed will bedescribed with reference to FIGS. 12 and 13. The pair of left and rightjoggers 31 can horizontally be moved with respect to a sheet dischargecenter position K1, and the right and left end faces of the sheet 100are jogged by the actuation of the pair of left and right joggers 31based on the sheet discharge center position K1 at which the sheet 100is conveyed. The rear end portion of the sheet 100 is supported by thesupport 20 located at the progressing position (Step a11).

After the right and left end faces of the sheet 100 are jogged, theright and left end faces of the sheet bundle 110 are moved rightwardfrom the sheet discharge center position K1 while sandwiched by the pairof left and right joggers 31, and the sheet bundle 110 is moved to astacking position K2 separated from the sheet discharge center positionK1 by a distance L1 (Step a12).

At the stacking position K2, the pair of left and right joggers 31 isopened, the leading end side of the jogged sheet bundle 110 is droppedon the stacking tray 3, and only the rear end portion of the sheetbundle 110 is placed on the support 20. At this point, the support 20 isretreated to drop and stack the rear end portion of the sheet bundle 110placed on the support 20 on the stacking tray 3 (Step a13). When thesheet bundle 110 is dropped on the stacking tray 3, the air escapes fromthe leading end side to the rear end side of the dropped sheet bundle110. Therefore, the stacked sheet bundle 110 is not displaced by theair.

Then, the pair of left and right joggers 31 is moved to the sheetdischarge center position K1, the right and left end faces of thenext-sent sheet 100 are jogged by the actuation of the pair of left andright joggers 31 based on the sheet discharge center position K1, andthe rear end side of the sheet 100 is supported by the support 20located at the progressing position (Step a14).

After the right and left end faces of the sheet 100 are jogged, theright and left end faces of sheet bundle 110 are moved leftward from thesheet discharge center position K1 while sandwiched by the pair of leftand right joggers 31, and the sheet bundle 110 is moved to a stackingposition K3 separated from the sheet discharge center position K1 by adistance L2 (Step a15).

At the stacking position K3, the pair of left and right joggers 31 isopened, the leading end side of the jogged sheet bundle 110 is droppedon the stacking tray 3, and only the rear end portion of the sheetbundle 110 is placed on the support 20. At this point, the support 20 isretreated to drop and stack the rear end portion of the sheet bundle 110placed on the support 20 on the stacking tray 3 (Step a16). When thesheet bundle 110 is dropped on the stacking tray 3, the air escapes fromthe leading end side to the rear end side of the dropped sheet bundle110. Therefore, the stacked sheet bundle 110 is not displaced by theair.

Thus, the operation to move the sheet bundle 110 in one of thehorizontal directions while the sheet bundle 110 is jogged at the sheetdischarge center position K1, open the pair of left and right joggers 31at the stacking position K2, and retreat the support 20 to drop andstack the sheet bundle 110 on the stacking tray 3, and the operation tomove the sheet bundle 110 in the other of the horizontal directionswhile the sheet bundle 110 is jogged at the sheet discharge centerposition K1, open the pair of left and right joggers 31 at the stackingposition K3, and retreat the support 20 to drop and stack the sheetbundle 110 on the stacking tray 3 are repeated, and the sheet bundle 110is stacked on the stacking tray 3 while alternately displaced L3 (Stepa17).

[One-Way Stacking Actuation in the Case that Stapling is not Performed]

Steps a11 to a13 described in the shift stacking actuation in the casethat the stapling is not performed are repeatedly performed, butactuation from Step a14 is not performed. Thus, the operation to movethe sheet bundle 110 in one of the horizontal directions while the sheetbundle 110 is jogged at the sheet discharge center position K1, open thepair of left and right joggers 31 at the stacking position K2, andretreat the support 20 to drop and stack the sheet bundle 110 on thestacking tray 3 is repeated, and the sheet bundle 110 is stacked on thestacking tray 3 while not alternately displaced.

[Shift Stacking Actuation in the Case that Stapling is Performed]

The actuation in the case that the stapling is performed will bedescribed with reference to FIGS. 14 and 15. The pair of left and rightjoggers 31 can horizontally be moved with respect to the sheet dischargecenter position K1 at which the sheet 100 is conveyed, and the right andleft end faces of the sheet 100 are jogged by the actuation of the pairof left and right joggers 31 based on the sheet discharge centerposition K1. The rear end portion of the sheet 100 is supported by thesupport 20 located at the progressing position (Step a21).

After the right and left end faces of the sheet 100 are jogged, theright and left end faces of the sheet bundle 110 are moved rightwardfrom the sheet discharge center position K1 while sandwiched by the pairof left and right joggers 31, and the sheet bundle 110 is stapled at astapling position K4 using the stapling means (Step a22). After thestapling, the right and left end faces of the sheet bundle 110 are movedleftward while sandwiched between the pair of left and right joggers 31,and the sheet bundle 110 is returned to the stacking position K2 (Stepa23).

At the stacking position K2, the pair of left and right joggers 31 isopened, the leading end side of the stapled sheet bundle 110 is droppedon the stacking tray 3, and only the rear end portion of the sheetbundle 110 is placed on the support 20. At this point, the support 20 isretreated to drop and stack the rear end portion of the sheet bundle 110placed on the support 20 on the stacking tray 3 (Step a24).

Then, the pair of left and right joggers 31 is moved to the sheetdischarge center position K1, the right and left end faces of thenext-sent sheet 100 are jogged by the actuation of the pair of left andright joggers 31 based on the sheet discharge center position K1, andthe rear end portion of the sheet bundle 110 is supported by the support20 located at the progressing position (Step a25).

After the right and left end faces of the sheet 100 are jogged, theright and left end faces of sheet bundle 110 are moved rightward whilesandwiched by the pair of left and right joggers 31, and the staplingmeans performs the stapling at the stapling position K4 (Step a26).After the stapling, the right and left end faces of the sheet bundle 110are moved leftward while sandwiched between the pair of left and rightjoggers 31, and the sheet bundle 110 is returned to the stackingposition K3 (Step a27).

At the stacking position K3, the pair of left and right joggers 31 isopened, the leading end side of the stapled sheet bundle 110 is droppedon the stacking tray 3, and only the rear end portion of the sheetbundle 110 is placed on the support 20. At this point, the support 20 isretreated to drop and stack the rear end portion of the sheet bundle 110placed on the support 20 on the stacking tray 3 (Step a28).

Thus, the operation to move the sheet bundle 110 in one of thehorizontal directions while the sheet bundle 110 is jogged at the sheetdischarge center position K1, and staple the sheet bundle 110 at thestapling position K4 using the stapling means 40, the operation to moveand open the pair of left and right joggers 31 at the stacking positionK2, and retreat the support 20 to drop and stack the sheet bundle 110 onthe stacking tray 3, the operation to move the sheet bundle 110 in oneof the horizontal directions while the sheet bundle 110 is jogged at thesheet discharge center position K1, and staple the sheet bundle 110 atthe stapling position K4 using the stapling means 40, and the operationto move and open the pair of left and right joggers 31 at the stackingposition K3, and retreat the support 20 to drop and stack the sheetbundle 110 on the stacking tray 3 are repeated, and the sheet bundle 110is stacked on the stacking tray 3 while alternately displaced L3 (Stepa29).

[One-Way Stacking Actuation in the Case that Stapling is Performed]

Steps a21 to a24 described in the shift stacking actuation in the casethat the stapling is performed are repeatedly performed, but theactuation from Step a25 is not performed. Thus, the operation to movethe sheet bundle 110 in one of the horizontal directions while the sheetbundle 110 is jogged at the sheet discharge center position K1, andstaple the sheet bundle 110 at the stapling position K4 using thestapling means 40, and the operation to move and open the pair of leftand right joggers 31 at the stacking position K2, and retreat thesupport 20 to drop and stack the sheet bundle 110 on the stacking tray 3are repeated, and the sheet bundle 110 is stacked on the stacking tray 3while not alternately displaced.

INDUSTRIAL APPLICABILITY

The invention is applied to the sheet post-processing apparatusconnected to the image forming apparatus such as the copying machine andthe printer, the sheet bundle is stacked while not displaced, thestacking property of the sheet bundle is improved, and the sheetreceiving time can be shortened to improve the productivity.

REFERENCE SIGNS LIST

-   1 sheet post-processing apparatus-   2 apparatus body-   3 stacking tray-   10 sheet conveying means-   11 conveying guide-   12 conveying roller-   20 support-   30 jogger and stack means-   31 pair of left and right joggers-   31 a lower guide-   31 b upper guide-   34 c coupling guide-   32 slide lever-   33 protrusion-   34 arm-   35 auxiliary lever-   36 link-   37 safety switch-   38 moving body-   40 stapling means-   50 sheet bundle holder-   100 sheet-   110 sheet bundle-   200 conveyance driving means-   201 support driving means-   202 jogger driving means-   203 jogger movement driving means-   300 control device

1. A sheet post-processing apparatus comprising: sheet conveying meansfor conveying a sheet discharged by an image forming apparatus to astacking tray; jogger and stack means including a pair of left and rightjoggers that stacks the sheet discharged by the sheet conveying meanswhile supporting and jogging the sheet; and a support that is able to beprogressed and retreated, and supports a rear end portion of the sheetdischarged by the sheet conveying means at a progressing position,wherein the jogger and stack means is arranged above the stacking tray,the support is arranged between the stacking tray and the jogger andstack means, the sheet discharged by the sheet conveying means issupported by the pair of left and right joggers, the rear end portion ofthe sheet is placed on and jogged by the support located at theprogressing position to form a sheet bundle, the pair of left and rightjoggers is opened to drop the jogged sheet bundle on the stacking tray,and the support is retreated to drop and stack the rear end portion ofthe sheet bundle placed on the support on the stacking tray.
 2. Thesheet post-processing apparatus according to claim 1, wherein thesupport supports an inside in a width direction of the rear end portionof the sheet.
 3. The sheet post-processing apparatus according to claim1, wherein the pair of left and right joggers supports and jogs aleading end side portion and a leading end bottom portion of the sheetdischarged by the sheet conveying means, and the pair of left and rightjoggers is opened to drop a leading end side of the jogged sheet bundleon the stacking tray.
 4. The sheet post-processing apparatus accordingto claim 1, wherein the pair of left and right joggers is horizontallymovable with respect to a sheet discharge center position, operation tomove the sheet bundle in one of the horizontal directions while thesheet bundle is jogged at the sheet discharge center position, open thepair of left and right joggers at a stacking position, and retreat thesupport to drop and stack the sheet bundle on the stacking tray, andoperation to move the sheet bundle in the other of the horizontaldirections while the sheet bundle is jogged at the sheet dischargecenter position, open the pair of left and right joggers at the stackingposition, and retreat the support to drop and stack the sheet bundle onthe stacking tray are repeated, and the sheet bundle is stacked on thestacking tray while alternately displaced.
 5. The sheet post-processingapparatus according to claim 1, wherein the pair of left and rightjoggers is horizontally movable with respect to a sheet discharge centerposition, operation to move the sheet bundle in one of the horizontaldirections while the sheet bundle is jogged at the sheet dischargecenter position, open the pair of left and right joggers at the stackingposition, and retreat the support to drop and stack the sheet bundle onthe stacking tray is repeated, and the sheet bundle is stacked on thestacking tray while not alternately displaced.
 6. The sheetpost-processing apparatus according to claim 1, further comprisingstapling means for stapling the sheet bundle jogged by the pair of leftand right joggers, wherein the pair of left and right joggers is openedto drop the leading end side of the sheet bundle stapled by the staplingmeans on the stacking tray, only the rear end portion of the sheetbundle is placed on the support, and the support is retreated to dropand stack the rear end portion the sheet bundle placed on the support onthe stacking tray.
 7. The sheet post-processing apparatus according toclaim 6, wherein the pair of left and right joggers is horizontallymovable with respect to a sheet discharge center position, operation tomove the sheet bundle in one of the horizontal directions while thesheet bundle is jogged at the sheet discharge center position, andstaple the sheet bundle at a stapling position using the stapling means,operation to move and open the pair of left and right joggers at one ofstacking positions, and retreat the support to drop and stack the sheetbundle on the stacking tray, operation to move the sheet bundle in oneof the horizontal directions while the sheet bundle is jogged at thesheet discharge center position, and staple the sheet bundle at astapling position using the stapling means, and operation to move andopen the pair of left and right joggers at the other of stackingpositions, and retreat the support to drop and stack the sheet bundle onthe stacking tray are repeated, and the sheet bundle is stacked on thestacking tray while alternately displaced.
 8. The sheet post-processingapparatus according to claim 6, wherein the pair of left and rightjoggers is horizontally movable with respect to a sheet discharge centerposition, operation to move the sheet bundle only in one of thehorizontal directions while the sheet bundle is jogged at a sheetdischarge center position, and staple the sheet bundle at a staplingposition using the stapling means, and operation to move and open thepair of left and right joggers at one of stacking positions, and retreatthe support to drop and stack the sheet bundle on the stacking tray arerepeated, and the sheet bundle is stacked on the stacking tray while notalternately displaced.
 9. The sheet post-processing apparatus accordingto claim 6, wherein a sheet bundle holder is arranged at a positionwhere the sheet bundle jogged by the pair of left and right joggers isstapled, and the sheet bundle holder acts as a holding member for thesheet bundle to be stapled, and as a cover covering the stapling means.10. The sheet post-processing apparatus according to claim 1, whereinthe sheet post-processing apparatus is arranged above the image formingapparatus, and the sheet conveying means conveys the sheet sent from anupper portion of the image forming apparatus to the stacking tray.